Was asking about the weight because some manufacturers say that they put on smaller rotors to save weight. In theory that's correct of course, it's unsprung and rotational weight too so it's the right place to save any weight. But I doubt 40 g would make such a huge difference compared to the...
Another advantage with more powerful brakes is the possibility to use 1-finger braking. More fingers to grip the bar when it gets messy. Personal preference maybe...
Here is an interesting article on the subject: Ending the rotor size myth – Why you should have a bigger brake rotor at the back than the front | ENDURO Mountainbike Magazine
One of the editors actually went down from 220 mm to 200 mm because the brakes where too strong, or 200 mm was good...
I find it really odd that bike manufacturers still insist on 180 mm in the rear, even on analog trail bikes. There is absolutely no reason not to have 200 mm.
I think larger rotors are great for several reasons. Have upgraded my brakes recently and it is a big difference in performance obviously, more leverage.
Larger rotors mean better heat dissipation which is important when going downhill (like in bike parks) => Less chance of overheating and...
The motor rattles a bit when coasting on uneven surfaces, but not as pronunced as the Bosch CX motor (at least not in my experience). Some motors are quiet when they're new and only develops a rattle after a while when worn in a bit.